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Thu, 6 Nov 2025 15:26:11 +0000 (GMT) Message-ID: <5cf46757-6029-4ea6-9006-5dc36b00e664@linux.ibm.com> Date: Thu, 6 Nov 2025 20:56:11 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [tip: locking/urgent] futex: Optimize per-cpu reference counting To: "Peter Zijlstra (Intel)" Cc: Sebastian Andrzej Siewior , x86@kernel.org, linux-kernel@vger.kernel.org, linux-tip-commits@vger.kernel.org References: <20251106092929.GR4067720@noisy.programming.kicks-ass.net> <176242925149.2601451.16934943329668653196.tip-bot2@tip-bot2> From: Shrikanth Hegde Content-Language: en-US In-Reply-To: <176242925149.2601451.16934943329668653196.tip-bot2@tip-bot2> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=StmdKfO0 c=1 sm=1 tr=0 ts=690cbe18 cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=IkcTkHD0fZMA:10 a=6UeiqGixMTsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=VwQbUJbxAAAA:8 a=JfrnYn6hAAAA:8 a=BYWC0JrQTQFL7lp5G-AA:9 a=QEXdDO2ut3YA:10 a=1CNFftbPRP8L7MoqJWF3:22 a=cPQSjfK2_nFv0Q5t_7PE:22 X-Proofpoint-ORIG-GUID: h9gyzSmNBu3FSffTICO9Fc45vKd0khd4 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMTAxMDAxOCBTYWx0ZWRfX5kbiXUPHPK0A AbFnmADHnEYZ5H+7zivI8kmHI75w+xIHP9tyjJLvm9SYnvgqv8CvKEF0rYinH45a//DprfUIheC S0CrSfshlUd8aiJHOtnp+je/clXiAWC5ywPAzV5IlQ1NrN4klfDcHL7jbcOQAwZ1o3ZoR8ltUZK TRn21wCGCKXpby624ULiK4hsCj6+pNRuleKwRHWtA1GdTDvlMhaePVh2b1QJSA2RZCUWpLY6ZUN I4ra0dx42p2M+c0OsxbMAznrH654lWqo2PQ0B7XkxNKri34iEtY1aReVxpVlA1sprK8gnlRFTj3 04RO7I2wX1igQmSjncrlfGkAFoaGM3D8WafFSfVUSFG9JyNOdP9b3IB9tgz9JRCG24V0+VmBIXP A9AGrrBS9KMzgD00N79t1bbj87etNg== X-Proofpoint-GUID: h9gyzSmNBu3FSffTICO9Fc45vKd0khd4 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.100.49 definitions=2025-11-06_03,2025-11-06_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 phishscore=0 impostorscore=0 priorityscore=1501 malwarescore=0 clxscore=1011 adultscore=0 bulkscore=0 lowpriorityscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2510240000 definitions=main-2511010018 On 11/6/25 5:10 PM, tip-bot2 for Peter Zijlstra wrote: > The following commit has been merged into the locking/urgent branch of tip: > > Commit-ID: 4cb5ac2626b5704ed712ac1d46b9d89fdfc12c5d > Gitweb: https://git.kernel.org/tip/4cb5ac2626b5704ed712ac1d46b9d89fdfc12c5d > Author: Peter Zijlstra > AuthorDate: Wed, 16 Jul 2025 16:29:46 +02:00 > Committer: Peter Zijlstra > CommitterDate: Thu, 06 Nov 2025 12:30:54 +01:00 > > futex: Optimize per-cpu reference counting > > Shrikanth noted that the per-cpu reference counter was still some 10% > slower than the old immutable option (which removes the reference > counting entirely). > Thanks for picking it up.